The proposed research will examine the neural mechanisms controlling visual target selection and saccade generation. Can target selection be influenced by new perceptual information? If so, to what degree is the selection process modifiable over time? When does the decision to make a particular movement become irrevocable? Neural activity recorded from the frontal eye fields (FEF) of behaving monkeys in a novel task will allow the dissociation of mechanisms that select targets and control saccades. The search-step task is an elaboration of the standard visual search task. Monkeys will be trained to shift gaze to an oddball target among an array of distractors. On random infrequent trials the target and one distractor will be switched at variable intervals after array onset. Monkeys will be rewarded for canceling the original saccade and compensating with a saccade to the new target location. Performance will be analyzed with a race model to estimate the time needed to compensate for the target-distractor switch. To play a role in target selection, a neuron must discharge differently when the monkeys compensate for the target switch compared to responding to the original target location. This paradigm permits new insights into the roles of visual and movement neurons in the FEF.